a) Field of the Invention
The invention is directed to a tool turret for machine tools comprising a turret disk which can be positioned in determined rotational angle positions and is rotatable, via a gear unit, by a motor, wherein the gear unit also serves to drive a tool drive shaft which can be coupled in a conventional manner with tools which are held by the turret disk so as to be drivable.
b) Background Prior Art
A tool turret of this type is known from DE-PS 37 30 561. In practice, cases often arise in which a workpiece must be machined at two parallel surfaces simultaneously, wherein the demand arises that the cutting edge of the tool not be allowed to be guided back again along the machined surface after machining so as to prevent scoring during the return movement.
In order to solve this problem it is known to provide two carriages which are coupled with one another, i.e. drivable together with one another, in the direction of the x-axis, but which are drivable independently of one another in the direction of the z-axis in order to carry out the respective movements by which the cutting edge of the tool lifts off of the tool piece, which movements run in opposite directions with reference to the two cutting edges of the tool. This requires a high cost on construction, wherein this solution also has the disadvantage that the two carriages require a relatively large amount of space and are only insufficiently accessible due to the arrangement of the main spindle for the workpiece to be clamped and machined.
It is the object of the present invention to provide a solution which is simple in terms of construction and economizes on space and which, beyond this, enables an easy accessibility to the tools and achievement of good machining quality.
A tool turret for machine tools, according to the preamble of patent claim 1, as is known from DE-PS 37 30 561, is used in order to meet this object and is constructed, according to the present invention, in such a way that at least one tool holding device is provided at the turret disk instead of the drivable tools, which tool holding device comprises a base part and a tool holder which is displaceable and adjustable relative to the base part vertically with respect to the turret axis, that a feed gear unit for the tool holder is provided in the base part and can be coupled with the tool drive shaft, and that every tool holding device is provided with a tool holder for a tool which is located radially opposite to the radially displaceable tool, the tool holder being arranged so as to be fixed at the turret disk, wherein the displaceable and the fixed tool serves to simultaneously machine opposite sides of a workpiece.
This solution, which is based on a turret for machine tools, is simple with respect to construction and, as a result of the rotatable turret disk, this arrangement also provides easy accessibility to the tools. Moreover, this construction is extremely economical with respect to space, since only one carriage is provided with a tool turret. The simultaneous machining of two opposite sides of a workpiece enabled by the solution by means of tools which are arranged at a tool holding device at the turret head by means of tool holders and which can remain in the respective selected assignment relative to one another regardless of the turret head carriage movement results in an advantageous machining quality.
A machine tool holder unit is known from DE-OS 34 18 215 in which the rotation of the spindle is used for the radial adjustment of the tools, but no suggestion for the simultaneous machining of both sides of the workpiece by two tools arranged at a tool holding device can be gathered from this DE-OS.